The device was running the latest version of firmware, 4.30.14, but DefenseCode said the vulnerability is in all previous versions as well. "Exploit shown in this video has been tested on Cisco Linksys WRT54GL, but other Linksys versions/models are probably also affected," the company said in its blog post.

DefenseCode did not respond to questions sent via email.

In December, Cisco hired Barclays to find a buyer for Linksys, Bloomberg reported. The network equipment maker was looking to sell the unit as part of its strategy to get rid of its consumer businesses in order to focus on corporate products.

Also last year, Cisco had to deal with a firestorm of complaints from customers angry over the company's decision to have Linksys customers use an Internet-based administration service as the default tool for managing their routers.

Cisco later retreated and brought back as the default the traditional setup and management over the local network. Customers would have to opt-in to the cloud service, which raised concerns about privacy and having to accept automatic firmware updates.

This story, "Cisco investigates reported Linksys router flaw" was originally published by
CSO.